Underwater attitude precision evaluation device and evaluation method for unmanned underwater vehicle

Abstract

The invention discloses an underwater attitude precision evaluation device for an unmanned underwater vehicle. The underwater attitude precision evaluation device comprises a synchronous pulse generator, a controller, a liftable three-axis turntable, an unmanned underwater vehicle mounting tool, an industrial personal computer and a mounting bracket, the unmanned underwater vehicle is centrally fixed on the liftable three-axis turntable through the unmanned underwater vehicle mounting tool, and the liftable three-axis turntable can drive the unmanned underwater vehicle to simulate different postures by lowering to a specified underwater depth; in attitude precision evaluation, a synchronous pulse generator is utilized to send synchronous pulses to a controller and inertial navigation equipment at the same time, so that the liftable three-axis turntable and the inertial navigation equipment output an attitude information true value and an attitude information test value at the same moment to an industrial personal computer, and a precision result is obtained through calculation; according to the device and the method, research and development personnel have accurate underwater attitude motion information of the unmanned underwater vehicle when evaluating the precision of the attitude information of the unmanned underwater vehicle.

Description

Technical Field

[0001] The present invention relates to the technical field of underwater navigation accuracy evaluation of unmanned underwater vehicles, and particularly relates to an underwater attitude accuracy evaluation device and method for unmanned underwater vehicles. Background Art

[0002] An unmanned underwater vehicle is an underwater robot used to perform tasks such as underwater exploration, detection, and operation, and has the ability of autonomous or remote control navigation. Common unmanned underwater vehicles include remotely operated underwater vehicles and autonomous underwater vehicles; among them, the remotely operated underwater vehicle is controlled in real time by surface personnel through a cable and relies on external energy and instructions; while the autonomous underwater vehicle does not require real-time human intervention and relies on a preset program or artificial intelligence to perform tasks autonomously. For an autonomous underwater vehicle, in order to achieve high-precision attitude measurement and control, an inertial navigation device needs to be equipped for the autonomous underwater vehicle. Before the autonomous underwater vehicle is officially launched and used, it is necessary to evaluate the navigation attitude accuracy of the inertial navigation device to ensure that it can efficiently complete the specified operation tasks.

[0003] Among them, the inertial navigation device installed in the unmanned underwater vehicle can give real-time navigation information of the unmanned underwater vehicle including position, speed, and attitude, and provide navigation information for the long-time remote autonomous navigation of the unmanned underwater vehicle. The most important navigation information of the unmanned underwater vehicle underwater is attitude information, and the position and speed information can be provided and calibrated by a log installed on the unmanned underwater vehicle, but the attitude information is completely provided by the inertial navigation device, and the attitude accuracy completely depends on the attitude accuracy output by the inertial navigation device. Therefore, the accuracy evaluation of the attitude information provided by the inertial navigation device of the unmanned underwater vehicle is an important index for evaluating whether the inertial navigation device of the unmanned underwater vehicle is qualified. However, when the unmanned underwater vehicle is working underwater, due to the unpredictability of the underwater environment, it is difficult to obtain an accurate attitude information reference, resulting in difficulty for R & D personnel to accurately evaluate the accuracy of the attitude information of the inertial navigation device in the unmanned underwater vehicle. Summary of the Invention

[0004] The purpose of the present invention is to provide an underwater attitude accuracy evaluation device for an unmanned underwater vehicle that can realize the accuracy evaluation of the attitude information provided by the inertial navigation device of the unmanned underwater vehicle.

[0005] Another purpose of the present invention is to provide an underwater attitude accuracy evaluation method for an unmanned underwater vehicle implemented by using the above-mentioned underwater attitude accuracy evaluation device for an unmanned underwater vehicle.

[0006] To this end, the technical solution of the present invention is as follows:

[0007] An underwater attitude accuracy evaluation device for an unmanned underwater vehicle, comprising a synchronous pulse generator, a controller, a liftable three-axis turntable and an installation tooling for the unmanned underwater vehicle; wherein,

[0008] The liftable three-axis turntable includes a motor-driven lifting mechanism, an outer frame, a middle frame and an inner frame;

[0009] The outer frame includes an inverted U-shaped frame body, at the center of the top of which there is an outer frame motor, the output shaft of the outer frame motor is vertically upward and connected to the bottom of the lifting mechanism, so that the inverted U-shaped frame body rotates along the axis of the lifting mechanism; the outer frame encoder is arranged on the output shaft of the outer frame motor to measure the rotation angle of the output shaft of the outer frame motor in real time;

[0010] The middle frame includes a circular frame body arranged between the two vertical rods of the inverted U-shaped frame body, two middle frame motors are symmetrically fixed on the outer wall of the circular frame body, and the output shafts of the two are horizontally opposite, so as to be fixed to the bottom sides of the two vertical rods, so that the circular frame body can rotate relative to the inverted U-shaped frame body; the middle frame encoder is arranged on the output shaft of one of the middle frame motors to measure the rotation angle of the output shaft of the inner frame motor in real time;

[0011] The inner frame includes a circular disc embedded in the middle frame, two inner frame motors are symmetrically fixed on its annular outer wall, and the output shafts of the two are horizontally opposite, so as to be fixed to the inner wall of the circular frame body of the middle frame, so that the circular disc can rotate relative to the circular frame body; the inner frame encoder is arranged on the output shaft of one of the inner frame motors to measure the rotation angle of the output shaft of the inner frame motor in real time;

[0012] The connection line between the output shafts of the two middle frame motors is perpendicular to the connection line between the output shafts of the two inner frame motors, and the intersection point of the two connection lines is located on the central axis of the output shaft of the outer frame motor;

[0013] The installation tooling for the unmanned underwater vehicle is centrally fixed on the top surface of the circular disc, so that the unmanned underwater vehicle is centrally fixed in a horizontal state on the top surface of the circular disc;

[0014] The controller is respectively connected to the motors on the lifting mechanism, the outer frame, the middle frame and the inner frame to control the rotation direction and angle of each motor;

[0015] The synchronous pulse generator is respectively connected to the inner frame encoder, the middle frame encoder, the outer frame encoder and the inertial navigation device to send synchronous pulse signals to each encoder and the inertial navigation device simultaneously.

[0016] Further, the motor-driven lifting mechanism includes a motor, a lifting device, a sleeve, and a lifting rod. Among them, the lifting device uses a worm screw lift with the motor drive shaft and the screw perpendicular to each other, and it is fixed on the bottom surface of the mounting base with the screw vertically downward. The output shaft of the motor is connected to the motor drive shaft of the worm screw lift. The lifting rod is sleeved outside the screw, and its top is fixed to the bottom end of the screw nut to reciprocate on the screw along with the screw nut. The sleeve is sleeved outside the lifting rod, and its top is fixed to the lifting device, so that the lifting rod and the screw are located inside the sleeve.

[0017] Further, the installation tooling for the unmanned underwater vehicle is composed of a first mounting bracket, a second mounting bracket, a first mounting bracket cover plate, and a second mounting bracket cover plate. Among them, the first mounting bracket and the second mounting bracket are two U-shaped frames fastened to the circular disc of the inner frame at intervals by screws, so that the front side and the rear side of the unmanned underwater vehicle are respectively erected in the U-shaped through grooves of the first mounting bracket and the second mounting bracket. The first mounting bracket cover plate and the second mounting bracket cover plate are two inverted U-shaped frames respectively matching with the first mounting bracket and the second mounting bracket, and connecting ear plates are formed at the bottom ends of both of them extending outward in the horizontal direction, so that the first mounting bracket cover plate can be press-fitted on the front side of the unmanned underwater vehicle and detachably connected and fixed to the first mounting bracket by screws as a whole. The second mounting bracket cover plate can be press-fitted on the rear side of the unmanned underwater vehicle and detachably connected and fixed to the second mounting bracket by screws as a whole.

[0018] Further, the outer frame motor, the middle frame motor, and the inner frame motor all use micro servo motors; the inner frame encoder, the middle frame encoder, and the outer frame encoder all use angle encoders.

[0019] Further, a mounting base is connected to the top side of the lifting mechanism, and the mounting base is a horizontally arranged fixing plate.

[0020] Further, the underwater attitude accuracy evaluation device for the unmanned underwater vehicle further includes a mounting bracket, which is a Z-shaped frame body sequentially connected by a first horizontal plate, a vertical plate, and a second horizontal plate from top to bottom. The second horizontal plate is fixed at the edge of the pool, so that the first horizontal plate is above the water surface, and the mounting base is fixed on the bottom surface of the first horizontal plate.

[0021] Further, the controller uses a PLC controller.

[0022] Further, the underwater attitude accuracy evaluation device for the unmanned underwater vehicle further includes an industrial control computer, which is respectively connected to the inner frame encoder, the middle frame encoder, the outer frame encoder and the inertial navigation device, so that after each encoder and the inertial navigation device receive the synchronous pulse, they send the true value and the measured value of the attitude information of the unmanned underwater vehicle at the same moment to the industrial control computer, and then the industrial control computer processes to obtain the attitude accuracy result of the underwater unmanned vehicle.

[0023] A method for evaluating the attitude accuracy realized by an underwater attitude accuracy evaluation device for an unmanned underwater vehicle is as follows:

[0024] S1. Install the unmanned underwater vehicle, and control the liftable three-axis turntable to carry the unmanned underwater vehicle down to a specified underwater depth;

[0025] S2. Define the initial coordinate system of the unmanned underwater vehicle fixed on the inner frame of the liftable three-axis turntable as, and define the real-time coordinate system of the unmanned underwater vehicle fixed on the inner frame of the liftable three-axis turntable as:

[0026] S2. According to the initial coordinate system and the real-time coordinate system of the unmanned underwater vehicle defined in step S1, define the underwater attitude motion information of the unmanned underwater vehicle, including: heading angle, pitch angle and roll angle;

[0027] S3. Based on the definition in step S2, according to the need for evaluating the underwater attitude accuracy of the unmanned underwater vehicle, respectively control the outer frame, the middle frame and the inner frame to perform corresponding rotational motions in a specified manner to simulate the underwater motion attitude of the unmanned underwater vehicle. The true values of the heading angle, pitch angle and roll angle of the unmanned underwater vehicle are respectively obtained in real time by the outer frame encoder, the middle frame encoder and the inner frame encoder of the liftable three-axis turntable, that is, the true values of the attitude information for accuracy evaluation; while the inertial navigation device in the unmanned underwater vehicle provides the measured values of the heading angle, pitch angle and roll angle of the unmanned underwater vehicle in real time, that is, the measured values of the attitude information for accuracy evaluation;

[0028] S4. Use the synchronous pulse generator to send synchronous pulses to the controller and the inertial navigation device at the same time, so that the outer frame encoder, the middle frame encoder and the inner frame encoder transmit the true values of the heading angle, pitch angle and roll angle at the same moment to the industrial control computer; at the same time, when the inertial navigation device receives the synchronous pulse sent by the synchronous pulse generator, it also outputs the measured values of the heading angle, pitch angle and roll angle at the same moment to the industrial control computer;

[0029] S5. Based on the measured values of the attitude information and the true values of the attitude information of the unmanned underwater vehicle at the same moment, obtain the attitude accuracy including the heading angle accuracy, pitch angle accuracy and roll angle accuracy.

[0030] Furthermore, in step S5, the calculation formula for the attitude accuracy including the heading angle accuracy, pitch angle accuracy, and roll angle accuracy is as follows:

[0031] Δγ = ||γ g - γ c || max ,

[0032] Δα = ||α g - α c || max ,

[0033] Δβ = ||β g - β c || max ,

[0034] wherein, Δγ is the heading angle accuracy, γ g is the heading angle test value at the same moment, and γ c is the true heading angle value at the same moment; Δα is the pitch angle accuracy, and α g is the pitch angle test value at the same moment, and α c is the true pitch angle value at the same moment; Δβ is the roll angle accuracy, and β g is the roll angle test value at the same moment, and β c is the true roll angle value at the same moment; the operation symbol || || max means taking the absolute value of each value at different moments respectively and selecting the maximum value from these absolute values as the final result.

[0035] Compared with the prior art, the underwater attitude accuracy evaluation device and method for the unmanned underwater vehicle overcome the problem that it is difficult to obtain accurate attitude information reference for the unmanned underwater vehicle during underwater operation due to the unknowability of the underwater environment, enabling R & D personnel to have accurate underwater attitude motion information of the unmanned underwater vehicle when evaluating the accuracy of the attitude information of the unmanned underwater vehicle; the synchronous pulse generator can obtain the attitude information and attitude reference at the same moment, overcoming the signal transmission time delay error and improving the reliability of the attitude accuracy evaluation. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 is a schematic composition diagram of the underwater attitude accuracy evaluation device for the unmanned underwater vehicle of the present invention;

[0037] Figure 2 is a schematic structural composition diagram of the liftable three-axis turntable in the underwater attitude accuracy evaluation device for the unmanned underwater vehicle of the present invention;

[0038] Figure 3Schematic diagram of the structure composition of the unmanned underwater vehicle installation tooling in the underwater attitude accuracy evaluation device of the present invention;

[0039] Figure 4 Schematic diagram of the installation of the inertial navigation device in the unmanned underwater vehicle in the underwater attitude accuracy evaluation device of the present invention;

[0040] Figure 5 Schematic diagram of the installation of the unmanned underwater vehicle on the liftable three-axis turntable in the underwater attitude accuracy evaluation device of the present invention;

[0041] Figure 6 Schematic diagram of the definition of the heading angle of the unmanned underwater vehicle in the underwater attitude accuracy evaluation device of the present invention;

[0042] Figure 7 Schematic diagram of the definition of the pitch angle of the unmanned underwater vehicle in the underwater attitude accuracy evaluation device of the present invention;

[0043] Figure 8 Schematic diagram of the definition of the roll angle of the unmanned underwater vehicle in the underwater attitude accuracy evaluation device of the present invention;

[0044] Figure 9 Schematic diagram of the working state of the underwater attitude accuracy evaluation device of the unmanned underwater vehicle of the present invention on the water surface;

[0045] Figure 10 Schematic diagram of the working state of the underwater attitude accuracy evaluation device of the unmanned underwater vehicle of the present invention under the water surface;

[0046] Figure 11 Schematic diagram of the signal flow when the underwater attitude accuracy evaluation device of the unmanned underwater vehicle of the present invention performs attitude accuracy evaluation. Detailed implementation manners

[0047] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments, but the following embodiments are by no means any limitation to the present invention.

[0048] Refer to Figure 1 , the underwater attitude accuracy evaluation device of the unmanned underwater vehicle includes a synchronous pulse generator 1, a controller 2, a liftable three-axis turntable 3, an unmanned underwater vehicle installation tooling 4, an industrial control computer 7 and an installation bracket 8; specifically,

[0049] Refer to Figure 2 , the liftable three-axis turntable 3 includes an installation base 301, a motor 302, a lifting device 303, a sleeve 304, a lifting rod 305, an outer frame 306, a middle frame 307 and an inner frame 308; among them,

[0050] The installation base 301 is a horizontally arranged substrate.

[0051] The lifting device 303 specifically adopts a worm and screw lift, and its motor drive shaft is perpendicular to the screw; the worm and screw lift is arranged with the screw vertically downward, and the drive steering mechanism housing at its top is welded and fixed to the bottom surface of the installation base 301; in order to facilitate the installation of the motor 302, a connecting flange is vertically arranged on the drive shaft side of the drive steering mechanism housing, and the connecting flange is connected and fixed to the drive steering mechanism housing as a whole through a plurality of connecting rods arranged circumferentially and radially along its circumference; in order to facilitate the installation of the sleeve 304, a horizontally arranged connecting flange is welded and fixed to the bottom of the drive steering mechanism housing.

[0052] The output shaft of the motor 302 is connected to the motor drive shaft of the worm and screw lift through a coupling, so as to drive the motor drive shaft of the worm and screw lift to rotate synchronously through the motor 302, and further drive the screw nut in the worm and screw lift to move up and down relative to the screw; correspondingly, a connecting flange is welded and fixed to the end face on the output shaft side of the motor 302, so that the housing of the motor 302 and the drive steering mechanism housing are connected and fixed as a whole through the connecting flange.

[0053] As a preferred technical solution of this embodiment, four obliquely arranged reinforcing rods are evenly distributed along the circumferential direction between the installation base 301 and the drive steering mechanism housing of the worm and screw lift, and both ends of each reinforcing rod are welded and fixed to the bottom surface of the installation base 301 and the top surface of the drive steering mechanism housing respectively, so as to strengthen the structural connection strength between the installation base 301 and the lifting device 303.

[0054] See Figure 3 and Figure 4 , the sleeve 304 is a cylindrical barrel with an inner diameter larger than the screw nut of the worm and screw lift, and a connecting flange is provided at its top; the sleeve 304 is sleeved outside the screw with a gap from the screw nut of the worm and screw lift and is coaxially arranged with the screw. The top of the sleeve 304 and the drive steering mechanism housing are detachably fixed and connected as a whole through their connecting flanges, so that the screw is placed therein.

[0055] The lifting rod 305 is a hollow rod with an opening at the top and a closed bottom. Its outer diameter is smaller than the inner diameter of the sleeve 304, and its inner diameter is larger than the outer diameter of the lead screw. The lifting rod 305 is sleeved outside the lead screw with a clearance from the lead screw of the turbine screw lift and is coaxially arranged with the lead screw. The top end of the lifting rod 305 is welded and fixed to the bottom surface of the lead screw nut to move synchronously along the axial direction of the lead screw with the lead screw nut in the sleeve 304. The axial length of the lifting rod 305 is adapted to the reciprocating movement stroke length of the lead screw nut on the lead screw. In the initial state, the lead screw nut is located on the top side of the lead screw, and at this time, the bottom end of the lifting rod 305 is flush with the bottom end of the sleeve 304.

[0056] The outer frame 306 is composed of an inverted U-shaped frame body, an outer frame motor, and an outer frame encoder. Among them, the inverted U-shaped frame body is composed of a horizontal rod and two vertical rods respectively fixed at both ends of the horizontal rod. The outer frame motor is centrally fixed on the top surface of the inverted U-shaped frame body with its output shaft facing vertically upward, and the shaft end of its output shaft is inserted and fixed at the center of the bottom surface of the lifting rod 305, so that the inverted U-shaped frame body can rotate a specified angle along the axis of the lifting rod 305 under the drive of the outer frame motor. The outer frame encoder is arranged on the output shaft of the outer frame motor, specifically located between the inverted U-shaped frame body and the lifting rod 305, and is used to measure the rotation angle of the output shaft of the outer frame motor in real time.

[0057] The middle frame 307 is composed of a circular ring-shaped frame body, two middle frame motors, and a middle frame encoder. Among them, the outer diameter of the circular ring-shaped frame body is slightly smaller than the distance between the two vertical rods on the inverted U-shaped frame body, so that the circular ring-shaped frame body can be placed inside the two vertical rods of the inverted U-shaped frame body. The two middle frame motors are embedded and fixed in two motor mounting holes symmetrically opened on the outer wall of the circular ring-shaped frame body with their output shafts arranged horizontally and oppositely, and the shaft ends of their output shafts are inserted and fixed at the bottom ends of the two vertical rods of the inverted U-shaped frame body, so that the middle frame 307 can rotate relative to the outer frame 306 under the synchronous drive of the two middle frame motors. The middle frame encoder is arranged on the output shaft of one of the middle frame motors, specifically located between the circular ring-shaped support and any one of the vertical rods of the inverted U-shaped frame body, and is used to measure the rotation angle of the output shaft of the inner frame motor in real time.

[0058] The inner frame 308 is composed of a circular disk body, two inner frame motors, and an inner frame encoder; the outer diameter of the circular disk body is slightly smaller than the inner diameter of the circular ring-shaped frame body, enabling the circular disk body to be placed inside the circular ring-shaped frame body; the two inner frame motors are fixedly embedded in two motor mounting holes symmetrically opened on the circular disk body in such a way that their output shafts are horizontal and opposite, and the shaft ends of the two output shafts are inserted and fixed on the inner wall, enabling the inner frame 308 to rotate relative to the middle frame 307 under the synchronous drive of the two inner frame motors; the inner frame encoder is arranged on the output shaft of one of the inner frame motors, specifically located between the circular disk body and the circular ring-shaped support, and is used to measure the rotation angle of the output shaft of the inner frame motor in real time;

[0059] Among them, the connection line between the output shafts of the two middle frame motors is perpendicular to the connection line between the output shafts of the two inner frame motors, and the intersection point of the two connection lines is located on the central axis of the output shaft of the outer frame motor; the above-mentioned outer frame motor, middle frame motor, and inner frame motor all adopt micro servo motors; the above-mentioned inner frame encoder, middle frame encoder, and outer frame encoder all adopt angle encoders.

[0060] The installation tooling 4 for the unmanned underwater vehicle is fixedly centered on the top surface of the circular disk body of the inner frame 308 for installing the unmanned underwater vehicle 5 on the liftable three-axis turntable 3; specifically, the installation tooling 4 for the unmanned underwater vehicle is composed of a first installation bracket 401, a second installation bracket 402, a first installation bracket cover plate 403, and a second installation bracket cover plate 404; among them, the first installation bracket 401 and the second installation bracket 402 are two U-shaped frame bodies fixedly fastened to the circular disk body of the inner frame 308 at intervals by screws, and the horizontal length of the second installation bracket 402 is greater than the horizontal length of the first installation bracket 401, enabling the front side and the rear side of the unmanned underwater vehicle 5 to be respectively placed in the U-shaped through grooves of the first installation bracket 401 and the second installation bracket 402; the first installation bracket cover plate 403 and the second installation bracket cover plate 404 are two inverted U-shaped frame bodies respectively matched with the first installation bracket 401 and the second installation bracket 402, and connection ear plates are formed by extending outward horizontally from the bottom end sides of the two, enabling the first installation bracket cover plate 403 to be press-fitted on the front side of the unmanned underwater vehicle 5 and detachably connected and fixed to the first installation bracket 401 by screws as a whole; the second installation bracket cover plate 404 can be press-fitted on the rear side of the unmanned underwater vehicle 5 and detachably connected and fixed to the second installation bracket 402 by screws as a whole;

[0061] The unmanned underwater vehicle 5 is firmly fixed on the top surface of the circular disc of the inner frame 308 in a horizontal state; wherein, an inertial navigation device 6 is provided inside the unmanned underwater vehicle 5, which is used to provide real-time attitude information for the unmanned underwater vehicle 5 and serve as the test value for attitude accuracy evaluation; when initially used, the lifting rod 305 is in a retracted state, and the tester uses a ship as a water surface platform to install the unmanned underwater vehicle 5 on the inner frame 308; at this time, the unmanned underwater vehicle 5 installed on the inner frame 308 is above the water surface.

[0062] In practical applications, sealing devices (such as waterproof sealing rings or waterproof sleeves) are provided at all contact points where all moving parts of the liftable three-axis turntable 3 come into contact with water to prevent the water in the pool from entering the motors inside the liftable three-axis turntable 3; specifically including: the linear motion contact point between the lifting rod 305 and the lifting rod sleeve 304, the rotational motion contact point between the outer frame 306 and the lifting rod 305, the rotational motion contact point between the middle frame 307 and the outer frame 306, and the rotational motion contact point between the inner frame 308 and the middle frame 307; at the same time, the outer surface of the liftable three-axis turntable 3 is sprayed with anti-rust paint to prevent the liftable three-axis turntable 3 from rusting.

[0063] See Figure 9 , the mounting bracket 8 is a Z-shaped frame body formed by sequentially connecting a first horizontal plate, a vertical plate, and a second horizontal plate from top to bottom; the second horizontal plate of the mounting bracket 8 is fixed to the pool shore 9 by a plurality of bolts arranged circumferentially; the mounting base 301 of the liftable three-axis turntable 3 is fixed to the bottom surface of the first horizontal plate of the mounting bracket 8 by a plurality of bolts arranged circumferentially; in the initial state, the liftable three-axis turntable 3 is above the water surface of the pool.

[0064] The controller 2 is connected to the motor 302 to send motion command signals including attitude motion commands to each motor, so that the controller 2 controls the liftable three-axis turntable 3 to descend to a specified depth underwater or rise above the water surface through the motion command signals sent to the motor 302; the controller 2 is also connected to the outer frame motor, each middle frame motor, and each inner frame motor, and controls the outer frame 306, middle frame 307, and inner frame 308 of the liftable three-axis turntable 3 to rotate until the unmanned underwater vehicle 5 reaches a predetermined attitude, providing an attitude reference for the unmanned underwater vehicle 5 and serving as the true value for attitude accuracy evaluation; in this embodiment, the controller specifically uses a PLC controller;

[0065] The synchronous pulse generator 1 is respectively connected to the inner frame encoder, middle frame encoder, outer frame encoder, and inertial navigation device 6 to simultaneously send synchronous pulse signals to each encoder and the inertial navigation device 6;

[0066] The industrial control computer 7 is respectively connected to the inner frame encoder, the middle frame encoder, the outer frame encoder and the inertial navigation device 6, so that after each encoder and the inertial navigation device 6 receive the synchronization pulse (i.e., the pulse information generated at the same moment) sent by the synchronization pulse generator 1, they send the true value and the measured value of the attitude information of the unmanned underwater vehicle 5 at the same moment to the industrial control computer 7; furthermore, the industrial control computer 7 processes the true value and the measured value of the attitude information at this moment to calculate and obtain the attitude accuracy of the underwater unmanned vehicle 5.

[0067] Embodiment 2

[0068] See Figures 6 to 11 , the specific implementation steps of realizing the underwater attitude accuracy evaluation method of the unmanned underwater vehicle by using the underwater attitude accuracy evaluation device of the unmanned underwater vehicle are as follows:

[0069] S1. See Figure 10 , after the tester completes the installation of the unmanned underwater vehicle 5, immediately evacuates to the pool bank 9 on the water surface; controls the motor 302 to rotate through the controller 2, so that the lifting rod 305 of the liftable three-axis turntable 3 slowly extends downward until the unmanned underwater vehicle 5 is immersed in the specified depth underwater;

[0070] S2. Define the initial coordinate system of the unmanned underwater vehicle 5 fixed on the inner frame 308 of the liftable three-axis turntable 3 as: the center of gravity of the unmanned underwater vehicle 5 is the origin O of the initial coordinate system, the initial forward direction of the unmanned underwater vehicle 5 is the OX axis of the initial coordinate system, the initial upward direction of the unmanned underwater vehicle 5 is the OZ axis of the initial coordinate system, and the initial leftward direction of the unmanned underwater vehicle 5 is the OY axis of the initial coordinate system;

[0071] Define the real-time coordinate system of the unmanned underwater vehicle 5 fixed on the inner frame 308 of the liftable three-axis turntable 3 as: when the outer frame 306 or the middle frame 307 or the inner frame 308 of the liftable three-axis turntable 3 moves, the center of gravity of the unmanned underwater vehicle 5 is the origin O of the real-time coordinate system (since the unmanned underwater vehicle 5 has no translational motion on the liftable three-axis turntable 3, the origin of the real-time coordinate system coincides with the origin of the initial coordinate system), the real-time forward direction of the unmanned underwater vehicle 5 is the OX1 axis of the real-time coordinate system, the real-time upward direction of the unmanned underwater vehicle 5 is the OZ1 axis of the real-time coordinate system, and the real-time leftward direction of the unmanned underwater vehicle 5 is the OY1 axis of the real-time coordinate system;

[0072] S2. Define the underwater attitude motion information of the unmanned underwater vehicle 5, including the heading angle, the pitch angle and the roll angle, according to the initial coordinate system and the real-time coordinate system of the unmanned underwater vehicle 5 defined in step S1;

[0073] See Figure 6, the heading angle is defined as: when the outer frame 306 rotates, the projection γ of the included angle between the OX1 axis of the real-time coordinate system and the OX axis of the initial coordinate system on the plane OX1Y1 is the heading angle in the underwater attitude motion information of the unmanned underwater vehicle 5. The range of the heading angle is 0 to 360°, and it increases in the counterclockwise rotation direction of the outer frame 306 around the OZ axis of the initial coordinate system; furthermore, through the outer frame encoder of the liftable three-axis turntable 3, the real heading angle of the unmanned underwater vehicle 5 on the liftable three-axis turntable 3 can be measured in real time;

[0074] See Figure 7 , the pitch angle is defined as: when the middle frame 307 rotates, the projection α of the included angle between the OX1 axis of the real-time coordinate system and the OX axis of the initial coordinate system on the plane OX1Z1 is the pitch angle in the underwater attitude motion information of the unmanned underwater vehicle 5. The range of the pitch angle is 0 to 360°, and it increases in the counterclockwise rotation direction of the middle frame 307 around the OY axis of the initial coordinate system; furthermore, through the middle frame encoder of the liftable three-axis turntable 3, the real pitch angle of the unmanned underwater vehicle 5 on the liftable three-axis turntable 3 can be measured in real time;

[0075] See Figure 8 , the roll angle is defined as: when the inner frame 308 rotates, the projection β of the included angle between the OY1 axis of the real-time coordinate system and the OY axis of the initial coordinate system on the plane OY1Z1 is the roll angle in the underwater attitude motion information of the unmanned underwater vehicle 5. The range of the roll angle is 0 to 360°, and it increases in the counterclockwise rotation direction of the inner frame 308 around the OX axis of the initial coordinate system; furthermore, through the inner frame encoder of the liftable three-axis turntable 3, the real roll angle of the unmanned underwater vehicle 5 on the liftable three-axis turntable 3 can be measured in real time;

[0076] S3. See Figure 11 , based on the heading angle, pitch angle, and roll angle in the underwater attitude motion information of the unmanned underwater vehicle 5 defined in step S2, according to the need for evaluating the underwater attitude accuracy of the unmanned underwater vehicle 5, the controller 2 respectively sends the heading angle motion command γ z , the pitch angle motion command α z , and the roll angle motion command β z to the outer frame motor, middle frame motor, and inner frame motor of the liftable three-axis turntable 3, that is, driving the outer frame 306, middle frame 307, and inner frame 308 of the liftable three-axis turntable 3 to perform corresponding rotational motions in a specified manner to accurately simulate the underwater motion attitude of the unmanned underwater vehicle 5; due to the delay error and control accuracy error in the motor motion control, the heading angle, pitch angle, and roll angle of the unmanned underwater vehicle 5 are not equal to the heading angle motion command γ z , the pitch angle motion command α z , and the roll angle motion command β z; Based on this, the true values of the heading angle, pitch angle, and roll angle of the unmanned underwater vehicle 5 are obtained in real time by the outer frame encoder, middle frame encoder, and inner frame encoder of the liftable three-axis turntable 3, respectively, that is, the true values of the attitude information for accuracy evaluation; while the inertial navigation device 6 in the unmanned underwater vehicle 5 provides the measured values of the heading angle, pitch angle, and roll angle of the unmanned underwater vehicle 5 in real time, that is, the measured values of the attitude information for accuracy evaluation;

[0077] S4. To obtain accurate attitude accuracy, it is necessary to compare the measured values of the attitude information and the true values of the attitude information at the same moment; therefore, the synchronous pulse generator 1 is used to send synchronous pulses to the controller 2 and the inertial navigation device 6 at the same time, so that the outer frame encoder, middle frame encoder, and inner frame encoder transmit the true values of the heading angle γ c , pitch angle α c and roll angle β c at the same moment to the industrial control computer 7; at the same time, when the inertial navigation device 6 receives the synchronous pulse sent by the synchronous pulse generator 1, it also outputs the measured values of the heading angle γ g , pitch angle α g and roll angle β g at the same moment to the industrial control computer 7;

[0078] S5. Based on the measured values of the attitude information and the true values of the attitude information of the unmanned underwater vehicle 5 at the same moment, the attitude accuracy including the heading angle accuracy, pitch angle accuracy, and roll angle accuracy is calculated. The specific calculation formula is as follows:

[0079] Δγ = ||γ g -γ c || max ,

[0080] Δα = ||α g -α c || max ,

[0081] Δβ = ||β g -β c || max ,

[0082] where Δγ is the heading angle accuracy, γ g is the measured value of the heading angle at the same moment, γ c is the true value of the heading angle at the same moment; Δα is the pitch angle accuracy, α g is the measured value of the pitch angle at the same moment, α c is the true value of the pitch angle at the same moment; Δβ is the roll angle accuracy, β g is the measured value of the roll angle at the same moment, βc is the true value of the roll angle at the same moment; the operation symbol |||| max means taking the absolute value of each value at different times and selecting the maximum value from each absolute value as the final result;

[0083] S6. After completing the underwater attitude motion test of the unmanned underwater vehicle 5, the controller 2 controls the motor 302 to drive the lifting rod 305 to retract upward into the sleeve 304, thereby driving the unmanned underwater vehicle 5 to rise above the water surface; the tester disassembles the unmanned underwater vehicle 5 from the inner frame 308 of the liftable three-axis turntable 3 by using a boat as a water surface platform for disassembly operation, and dries the pool water on the surface of the liftable three-axis turntable 3 after disassembly to prevent the liftable three-axis turntable 3 from rusting.

[0084] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any equivalent modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of the patent of the present invention.

Claims

1. An underwater attitude accuracy evaluation device for an unmanned underwater vehicle, characterized in that It includes a synchronous pulse generator (1), a controller (2), a liftable three-axis turntable (3), and an unmanned underwater vehicle installation tooling (4); the liftable three-axis turntable (3) includes a lifting mechanism, an outer frame (306), a middle frame (307), and an inner frame (308); the outer frame (306) includes an inverted U-shaped frame body, with an outer frame motor centered at its top, the output shaft of the outer frame motor is vertically upward and connected to the bottom of the lifting mechanism, so that the inverted U-shaped frame body rotates along the axis of the lifting mechanism; an outer frame encoder is provided on the output shaft of the outer frame motor; the middle frame (307) includes an annular frame body arranged between the two vertical rods of the inverted U-shaped frame body, two middle frame motors are symmetrically fixed on the outer wall of the annular frame body, and their output shafts are horizontally opposite, and are fixed to the bottom sides of the two vertical rods, so that the annular frame body can rotate relative to the inverted U-shaped frame body, and a middle frame encoder is provided on the output shaft of one of the middle frame motors; the inner frame (308) includes a circular disk body embedded in the middle frame (307), two inner frame motors are symmetrically fixed on its annular outer wall, and their output shafts are horizontally opposite, and are fixed to the inner wall of the annular frame body of the middle frame (307), so that the circular disk body can rotate relative to the circular annular frame body, and an inner frame encoder is provided on the output shaft of one of the inner frame motors; the connection line between the output shafts of the two middle frame motors and the connection line between the output shafts of the two inner frame motors are perpendicular to each other, and the intersection point of the two connection lines is located on the central axis of the output shaft of the outer frame motor; the unmanned underwater vehicle installation tooling (4) is centered and fixed on the top surface of the circular disk body, so that the unmanned underwater vehicle (5) is centered and fixed in a horizontal state on the top surface of the circular disk body; the controller (2) is electrically connected to the motors on the lifting mechanism, the outer frame, the middle frame, and the inner frame respectively, to control the rotation direction and angle of each motor; the synchronous pulse generator (1) is connected to the inner frame encoder, the middle frame encoder, the outer frame encoder, and the inertial navigation device (6) respectively, to send synchronous pulse signals simultaneously.

2. The underwater attitude accuracy evaluation device for an unmanned underwater vehicle according to claim 1, characterized in that, The electric lifting mechanism includes a motor (302), a lifting device (303), a sleeve (304), and a lifting rod (305); wherein, the lifting device (303) adopts a worm gear screw elevator with the motor drive shaft and the screw perpendicular to each other, and it is fixed to the bottom surface of the installation base (301) with the screw vertically downward; the output shaft of the motor (302) is connected to the motor drive shaft of the worm gear screw elevator; the lifting rod (305) is sleeved outside the screw, and its top is fixed to the bottom end of the screw nut, so as to reciprocate on the screw along with the screw nut; the sleeve (304) is sleeved outside the lifting rod (305), and its top is fixed to the lifting device (303), so that the lifting rod (305) and the screw are located inside the sleeve (304).

3. The underwater attitude accuracy evaluation device for an unmanned underwater vehicle according to claim 1, characterized in that, The installation tooling (4) for the unmanned underwater vehicle consists of a first installation bracket (401), a second installation bracket (402), a first installation bracket cover plate (403) and a second installation bracket cover plate (404); among them, the first installation bracket (401) and the second installation bracket (402) are two U-shaped frames fastened to the circular disc of the inner frame (308) at intervals by screws, so that the front side and the rear side of the unmanned underwater vehicle (5) are respectively erected in the U-shaped through grooves of the first installation bracket (401) and the second installation bracket (402); the first installation bracket cover plate (403) and the second installation bracket cover plate (404) are two inverted U-shaped frames respectively matched with the first installation bracket (401) and the second installation bracket (402), and connecting ear plates are formed at the bottom ends of both of them and extend outward in the horizontal direction, so that the first installation bracket cover plate (403) can be press-fitted on the front side of the unmanned underwater vehicle (5) and detachably connected and fixed to the first installation bracket (401) by screws; the second installation bracket cover plate (404) can be press-fitted on the rear side of the unmanned underwater vehicle (5) and detachably connected and fixed to the second installation bracket (402) by screws.

4. The underwater attitude accuracy evaluation device for an unmanned underwater vehicle according to claim 1, characterized in that, The outer frame motor, the middle frame motor and the inner frame motor all adopt micro servo motors; the inner frame encoder, the middle frame encoder and the outer frame encoder all adopt angle encoders.

5. The underwater attitude accuracy evaluation device for an unmanned underwater vehicle according to claim 1, characterized in that, An installation base (301) is connected to the top side of the lifting mechanism, and the installation base (301) is a horizontally arranged fixed plate.

6. The underwater attitude accuracy evaluation device for an unmanned underwater vehicle according to claim 5, characterized in that It further includes an installation bracket (8), which is a Z-shaped frame body formed by sequentially connecting a first horizontal plate, a vertical plate and a second horizontal plate from top to bottom; the second horizontal plate is fixed at the pool bank (9), so that the first horizontal plate is located above the water surface, and the installation base (301) is fixed on the bottom surface of the first horizontal plate.

7. The underwater attitude accuracy evaluation device for an unmanned underwater vehicle according to claim 1, characterized in that The controller adopts a PLC controller.

8. The underwater attitude accuracy evaluation device for an unmanned underwater vehicle according to claim 1, wherein, It further includes an industrial control computer (7), which is respectively connected to the inner frame encoder, the middle frame encoder, the outer frame encoder and the inertial navigation device (6), so that after each encoder and the inertial navigation device (6) receive a synchronous pulse, they send the true value and the measured value of the attitude information of the unmanned underwater vehicle (5) at the same moment to the industrial control computer (7), and then the industrial control computer (7) processes to obtain the attitude accuracy result of the underwater unmanned vehicle (5).

9. A method for evaluating attitude accuracy implemented by the underwater attitude accuracy evaluation device of the unmanned underwater vehicle according to any one of claims 1 to 8, characterized in that, The steps are as follows: S1. Install the unmanned underwater vehicle (5), and control the liftable three-axis turntable (3) to drive the unmanned underwater vehicle (5) to descend to a specified underwater depth; S2. Define the initial coordinate system of the unmanned underwater vehicle (5) fixed on the inner frame (308) of the liftable three-axis turntable (3) as, and define the real-time coordinate system of the unmanned underwater vehicle (5) fixed on the inner frame (308) of the liftable three-axis turntable (3) as: S2. According to the initial coordinate system and the real-time coordinate system of the unmanned underwater vehicle (5) defined in step S1, define the underwater attitude motion information of the unmanned underwater vehicle (5), including: heading angle, pitch angle and roll angle; S3. Based on the definition in step S2, according to the need for evaluating the underwater attitude accuracy of the unmanned underwater vehicle (5), the outer frame (306), the middle frame (307), and the inner frame (308) are respectively controlled to perform corresponding rotational motions in a specified manner to simulate the underwater motion attitude of the unmanned underwater vehicle (5). The true values of the heading angle, pitch angle, and roll angle of the unmanned underwater vehicle (5) are obtained in real time by the outer frame encoder, middle frame encoder, and inner frame encoder of the liftable three-axis turntable (3), that is, the true values of the attitude information for accuracy evaluation. The inertial navigation device (6) in the unmanned underwater vehicle (5) provides the measured values of the heading angle, pitch angle, and roll angle of the unmanned underwater vehicle (5) in real time, that is, the measured values of the attitude information for accuracy evaluation. S4. The synchronous pulse generator (1) is used to send synchronous pulses to the controller (2) and the inertial navigation device (6) simultaneously, so that the outer frame encoder, middle frame encoder, and inner frame encoder transmit the true values of the heading angle, pitch angle, and roll angle at the same moment to the industrial control computer (7). At the same time, when the inertial navigation device (6) receives the synchronous pulse sent by the synchronous pulse generator (1), it also outputs the measured values of the heading angle, pitch angle, and roll angle at the same moment to the industrial control computer (7). S5. Based on the measured values of the attitude information and the true values of the attitude information of the unmanned underwater vehicle (5) at the same moment, the attitude accuracy including the heading angle accuracy, pitch angle accuracy, and roll angle accuracy is obtained.

10. A method for evaluating attitude accuracy implemented by the underwater attitude accuracy evaluation device of an unmanned underwater vehicle according to claim 9, characterized in that, In step S5, the calculation formulas for the attitude accuracy including the heading angle accuracy, pitch angle accuracy, and roll angle accuracy are as follows: Δγ = ||γ g -γ c || max , Δα = ||α g -α c || max , Δβ = ||β g -β c || max , where Δγ is the heading angle accuracy, γ g is the heading angle test value at the same moment, γ c is the true heading angle value at the same moment; Δα is the pitch angle accuracy, α g is the pitch angle test value at the same moment, α c is the true pitch angle value at the same moment; Δβ is the roll angle accuracy, β g is the roll angle test value at the same moment, β c is the true roll angle value at the same moment; the operation symbol |||| max means taking the absolute value of each value at different moments respectively and selecting the maximum value from these absolute values as the final result.

Images